To counter United Liberation Front of Assam's targeted attacks on migrant workers, Army has launched major operations in Upper Assam and in areas surrounding the capital Guwahati to strike at terrorist bases and urban hideouts.

"A major operation is on for the past 15 days and we are achieving success in hitting ULFA and its sister militant outfits," top army sources said in New Delhi on Friday.

In the operations, besides ULFA, troops are also hitting sanctuaries and bases of outfits like National Democratic front of Bodoland and Manipur-based Kangleipak National Liberation Front.

They said in ongoing operations which were being launched on 'hard intelligence' seven militants had been killed so far and a number of others apprehended.

In the manhunt, army has come across a lot of latest arms, like American and Russian-made assault rifles and explosives, which they believe the terrorist outfits have clandestinely acquired taking advantage of the lull prompted by a prolonged ceasefire with them.

As part of the operations, a unit of the 11th Marathas on a 'raid and strike' mission last night hit a big group of KNLF militants deep inside the Kaziranga National Park killing two insurgents and apprehending a few others.

Nearly 8,000 troops are engaged in operations in and around Guwhati and parts of Karbi Anglong, on the Guwhati-Dimapur national highway, some of the areas where a number of migrant workers and their families have been targeted.

Simultaneously, troops have launched another vigorous drive in three Upper Assam districts of Dhibrugarh, Tinsukia and Jorhat.

In this sector about 12,000 troops have been fanned out in the hunt for militant bases and hideouts.

In an operation launched by the 21 Jat regiment near Gauripur, two militants were killed and some apprehended with arms and ammunition.

According to army sources, troops engaged in the hunt are coming across a huge amount of cash, which they believe have been secured by the militants through extortion.

Contingents of troops are also scouring the thick jungles on the border between Assam and Arunachal Pradesh, where ULFA and other militant cadres are known to have located their new training camps and headquarters.

"The operations would continue till the time we don't wipe out most of these new training camps and hideouts," senior army officers said.